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Gill Senior Member Joined: 11/11/2006 Location: AustraliaPosts: 669
Posted: 09:18am 26 May 2007
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It was just after the release of the new motors that we all started looking at 7 phase, this being the least expensive way to utilise the new cogless feature.
We grasped the Star configuration quickly but Delta was somewhat elusive. I came up with the Inde (Independent)connection of running each phase to a bridge rectifier first then parallelling the outputs. This gives the same as Delta minus the losses from the extra diodes.
Well I just cracked the 7 Phase Delta configuration for those running two hubs or wanting to fit Star/Delta switches.
If poles are numbered 1 to 7, do not link 1 to 2, 2 to 3, 3 to 4 etc. as in 3 phase, Link1 to 3, 3 to 5, 5 to 7, 7 to 2, 2 to 4, 4 to 6, and 6 back to 1.
For those running the Independent configuration in Parallel (IndeP, aka open delta) to avoid harmonics, by connecting the bridges in series (IndeS) you get the same output as Star minus the extra diode loss.
So in summary, with 3 and 7 phase, we have Star and Delta switching before the rectifier giving minimal diode losses but prone to harmonic losses, and IndeS and IndeP switching after the rectifier with no harmonic losses but double the diode losses.
Don't you just love freedom of choice?Edited by Gill 2007-05-27was working fine... til the smoke got out.
Cheers Gill _Cairns, FNQ
Highlander Senior Member Joined: 03/10/2006 Location: AustraliaPosts: 266
Posted: 01:29am 27 May 2007
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Well done Gill Can you do a rough wiring drawing and scan it?
Central Victorian highlands